Luminaires are controlled by luminaire controllers which are either mounted directly on the luminaire or are mounted on an interface receptacle provided on the luminaire. Such luminaire controllers tend to be implemented as either an analogue-controlled system using ‘0-10V’ protocol or a digitally-controlled system using digital addressable lighting interface (DALI) protocol for controlling dimming of associated luminaires and do not have the capability of being configured for operation either as an analogue-controlled system or as a digitally-controlled system when mounted on a luminaire due to the configuration of the luminaire. This is particularly the case where an interface receptacle is provided on the luminaire for receiving a luminaire controller as each interface receptacle is configured for either analogue (‘0-10V’) or digital (DALI) operation. This means that the correct type of luminaire controller needs to provided to meet the operational requirements of the luminaire and/or its associated interface receptacle in terms of polarity and for the prevention of miswiring.
U.S. Pat. No. 8,072,164 discloses a unified ‘0-10V’ and DALI dimming interface circuit for a ballast for dimming a lighting device. The unified dimming circuit is designed to be compatible with the polarity of connections within the ballast so that it is not damaged by miswired connections. In particular, the disclosed unified interface circuit includes an isolating inverter circuit coupled to both a voltage regulator and a current regulator, and a depolarising circuit to ensure that the correct polarity is provided to a rectifier circuit inductively-coupled to the isolating inverter circuit.